On Fri, Oct 04, 2024 at 02:07:39PM +0900, Damien Le Moal wrote:
> Introduce the function pci_epc_mem_map() to facilitate controller memory
> address allocation and mapping to a RC PCI address region in endpoint
> function drivers.
>
> This function first uses pci_epc_map_align() to determine the controller
> memory address size (and offset into) depending on the controller
> address alignment constraints. The result of this function is used to
> allocate a controller physical memory region using
> pci_epc_mem_alloc_addr() and map that memory to the RC PCI address
> space with pci_epc_map_addr().
>
> Since pci_epc_map_align() may indicate that the effective mapping
> of a PCI address region is smaller than the user requested size,
> pci_epc_mem_map() may only partially map the RC PCI address region
> specified. It is the responsibility of the caller (an endpoint function
> driver) to handle such smaller mapping.
>
> The counterpart of pci_epc_mem_map() to unmap and free the controller
> memory address region is pci_epc_mem_unmap().
>
> Both functions operate using a struct pci_epc_map data structure
> Endpoint function drivers can use struct pci_epc_map to access the
> mapped RC PCI address region using the ->virt_addr and ->pci_size
> fields.
>
> Co-developed-by: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>
> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@xxxxxxxxx>
> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> drivers/pci/endpoint/pci-epc-core.c | 78 +++++++++++++++++++++++++++++
> include/linux/pci-epc.h | 4 ++
> 2 files changed, 82 insertions(+)
>
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 48dd3c28ac4c..5f3b0a86d6fe 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -522,6 +522,84 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> }
> EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>
> +/**
> + * pci_epc_mem_map() - allocate and map a PCI address to a CPU address
> + * @epc: the EPC device on which the CPU address is to be allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the CPU address should be mapped
> + * @pci_size: the number of bytes to map starting from @pci_addr
> + * @map: where to return the mapping information
> + *
> + * Allocate a controller memory address region and map it to a RC PCI address
> + * region, taking into account the controller physical address mapping
> + * constraints using pci_epc_map_align().
> + * The effective size of the PCI address range mapped from @pci_addr is
> + * indicated by @map->pci_size. This size may be less than the requested
> + * @pci_size. The local virtual CPU address for the mapping is indicated by
> + * @map->virt_addr (@map->phys_addr indicates the physical address).
> + * The size and CPU address of the controller memory allocated and mapped are
> + * respectively indicated by @map->map_size and @map->virt_base (and
> + * @map->phys_base).
> + *
> + * Returns 0 on success and a negative error code in case of error.
> + */
> +int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> + u64 pci_addr, size_t pci_size, struct pci_epc_map *map)
> +{
> + int ret;
> +
> + ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, pci_size, map);
> + if (ret)
> + return ret;
> +
> + map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
> + map->map_size);
> + if (!map->virt_base)
> + return -ENOMEM;
> +
> + map->phys_addr = map->phys_base + map->map_ofst;
> + map->virt_addr = map->virt_base + map->map_ofst;
> +
> + ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
> + map->map_pci_addr, map->map_size);
> + if (ret) {
> + pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> + map->map_size);
> + map->virt_base = 0;
> + return ret;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_map);
> +
> +/**
> + * pci_epc_mem_unmap() - unmap and free a CPU address region
> + * @epc: the EPC device on which the CPU address is allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @map: the mapping information
> + *
> + * Unmap and free a CPU address region that was allocated and mapped with
> + * pci_epc_mem_map().
> + */
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> + struct pci_epc_map *map)
> +{
> + if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> + return;
> +
> + if (!map || !map->virt_base)
> + return;
> +
> + pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
> + pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> + map->map_size);
> + map->map_size = 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
> +
> /**
> * pci_epc_clear_bar() - reset the BAR
> * @epc: the EPC device for which the BAR has to be cleared
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 9df8a83e8d10..97d2fbb740fd 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -315,6 +315,10 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> phys_addr_t *phys_addr, size_t size);
> void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> void __iomem *virt_addr, size_t size);
> +int pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> + u64 pci_addr, size_t pci_size, struct pci_epc_map *map);
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> + struct pci_epc_map *map);
>
> #else
> static inline void pci_epc_init_notify(struct pci_epc *epc)
> --
> 2.46.2
>
Naming is one of the hardest problems in computer science :)
Perhaps:
s/pci_epc_mem_map()/pci_epc_mem_alloc_map()/
s/pci_epc_mem_unmap()/pci_epc_mem_free_unmap()/
is slightly more clear that this both allocates and maps.
Regardless:
Reviewed-by: Niklas Cassel <cassel@xxxxxxxxxx>
